World Economic and Financial Surveys

World Economic Outlook

Database—WEO Groups and Aggregates Information

April 2013

Country Composition of WEO Groups

The country classification in the World Economic Outlook divides the world into two major groups: advanced economies and emerging and developing economies. Please refer to the introduction to the WEO's Statistical Appendix for details. This classification is not based on strict criteria, economic or otherwise, but instead has evolved over time with the objective of facilitating analysis by providing a reasonably meaningful organization of the data.

Some countries remain outside the country classification and therefore are not included in the analysis. Anguilla, Cuba, the Democratic People’s Republic of Korea, and Montserrat are examples of countries that are not IMF members, and their economies therefore are not monitored by the IMF. Palau and Somalia are omitted from the emerging market and developing economies group composites because of data limitations.

WEO Aggregates

Composite data for country groups in the World Economic Outlook are either sums or weighted averages of data for individual countries. All historical and projected data are recalculated to reflect changes in country group composition in order to ensure that the economic indicators reflect changes in economic conditions and not changes in the country group composition. Arithmetically weighted averages are used for all data except inflation for the other emerging market and developing country group, for which geometric averages are used. The following conventions apply.

Country group composites for interest rates are weighted by GDP converted to U.S. dollars at market exchange rates (averaged over the preceding three years) as a share of group GDP.

Composites for other data relating to the domestic economy, whether growth rates or ratios, are weighted by GDP valued at purchasing power parities (PPPs) as a share of total world or group GDP. Annual inflation rates are simple percent change from previous years, except for other emerging market and developing countries where the rates are based on logarithmic differences (see the FAQ for more details).

Composites for data relating to the domestic economy for the euro area (17 member countries throughout the entire period unless otherwise noted) are aggregates of national source data using GDP weights. Annual data are not adjusted for calendar day effects. For data prior to 1999, data aggregation apply 1995 European Currency exchange rates.

Composite unemployment rates are weighted by labor force as a share of group labor force.

Composites relating to the external economy are sums of individual country data after conversion to U.S. dollars at the average market exchange rates in the years indicated for balance of payments data and at end-of-year market exchange rates for debt denominated in currencies other than U.S. dollars. Composites of changes in foreign trade volumes and prices, however, are arithmetic averages of percentage changes for individual countries weighted by the U.S. dollar value of exports or imports as a share of total world or group exports or imports (in the preceding year).

Composites for fiscal data are calculated as the sum of the U.S dollar values for the relevant individual countries.

Unless noted otherwise, group composites are computed if 90 percent or more of the share of group weights is represented.